Thanks for the suggestions - I think maybe the way the boiler modulates has something to do with the problem and we're learning to live with it. The installer balanced and bled the radiators so I don't think cause of the problem is in the radiators. I'm setting the room thermostat on auto in the...
I had a new Viessmann combination boiler fitted two weeks ago replacing a conventional boiler. Even during commissioning it took a long time (over an hour) before the radiators finally became hot. The boiler keeps cycling and first thing in the morning it can take two to three hours before the...